United States Environmental Protection Agency, Region 9

Air Division

Technical Support Document

for

EPA’s Notice of Rulemaking

for the

California State Implementation Plan

Placer County Air Pollution Control District’s

Rule 2 33

, Biomass Boil ers

Prepared by: Idalia Perez

Ju ly 20 11Placer County Air Pollution Control District (PCAPCD)

Submitted Rule PCAPCD Rule 233, Biomass Boilers:

 Adopted: December 10, 2009

 Submitted: May 17 , 2010

 Determined complete: June 8 , 2010

Previous Ru le Submittals There are no outstanding submittals of Rule 233. PCAPCD adopted a previous version of Rule 233 on October 11, 2007 and it was submitted to EPA on March 7, 2008. This rule was officially

withdrawn on November 5, 2008

.

SIP

- Approved Rule

 Adopte d: October 6, 1994

 Approved by EPA: April 30, 1996 ( 61 FR 18959 )

Rule Summary

Rule 2 33 regulates emissions of oxides of nitrogen ( NO x ) and carbon mo no x ide (CO) from

biomass boilers and ste a m generators that have a heat input rating of less than 500 millio n British Thermal Units per hour (MM Btu ) and a potential to emit 25 tons or more of NOx per year

.

Changes to the rule

The District amended Rule 233 on October 11, 2007 to address concerns from industry

. Regulated facilities were having difficulty meeting the parts per million ( ppm ) NOx limits during

start

- up and shutdown due to the carbon dioxide ( CO 2 ) correction in this form of the standard

. Facilities were able to meet their permitted pounds per hour ( lb/ hour ) NOx limit during the same periods of time b ecause t his form of the emission limit does not have a CO 2 correction. The NOx limits in the rule are shown in the following table.

Type of Boiler Limits during normal operations (ppm) Approximate l imits during

normal operations (lb/hour) 1 Limits durin g startup shutdown ( lb/hour ) Circulating Fluidized Bed 115 95.1 35

Stoker 115 59.7 37.6

The main changes to Rule 233 to address the facilities’ concerns were changes in the definitions

of start

- up, shutdown and the replacement of the existing ppm limi ts with lb/hour limits during these periods. Additionally, a 40 0 ppm or 1000 ppm limit for CO was added (depending on boiler type)

, the option for 50% reduction of NOx emissions from uncontrolled levels as the limit

for NOx was eliminated and the method fo r determining the HHV for fuel was changed from

ASTM D 2015

- 85 to ASTM E711

.

1 These values are not in the text of the rule, but were obtained from an email sent by John Finnell to Idalia Perez on

4/8/2011 . They are calculated based on the res pective boiler capacit ies of the two facilities currently regulated under

Rule 233.Other changes to the rule include added definitions and recordkeeping requirements that improve

rule clarity and enforceability.

Effects on Emissions The changes made to Rule 23 3 have no net effect on emissions . The removal of the 115 ppm

NOx limit during startup and shutdown will not result in a net increase in emissions because the 115 ppm limit will be replaced by lb/ hour limits during startup and shutdown

. As indicated by

th e table above, the new limits are more stringent on a lb/hour basis than the 115 ppm limit with respect to each of the two facilities that is currently regulated under Rule 233. The new limits will not result in a net decrease in emissions, s ince the limit s a re already in the facilities’ permits

.

Rule Evaluation Criteria We have primarily used the following three criteria to evaluate Rule 233 :

1. Rule Stringency

– Section 172(c)(1) of the Clean Air Act ( CAA) requires nonattainment areas to implement all rea sonably available control measures (RACM), including such reductions in emissions from existing sources in the area as may be obtained through the adoption, at a minimum, of reasonably available control technology (RACT), as expeditiously as practicable. I n addition, ozone nonattainment areas classified as moderate or above must require RAC T for all major sources of NOx

. CAA § 182(b)(2) & (f) ; 40 CFR § 51.912(a) . The PCAPCD regulates an ozone nonattainment area that is classified as Severe

- 15

under both the 1

- hr ozone and 8

- hr ozone standards

. 40 C.F.R. § 81.305 (2010)

. 2

Therefore, submitted Rule 233 must fulfill RACT requirements for NOx

.

2. Enforceability

– CAA s ection 110(a)(2)(A) requires that regulations submitted to EPA for approval into a State Implemen tation Plan (SIP) must be clear and legally enforceable.

3. SIP Revisions

- CAA s ection 110(l) prohibits EPA from approving any SIP

revision that would interfere with any applicable requirement concerning attainment and reasonable further progress (RFP) or any other ap plicable requirement of the CAA. In addition, CAA s ection 193 prohibits the modification of any SIP

- approved control requirement in effect before November 15, 1990 , in a

nonattainment area

.

Guidance and policy documents that we used to define specific enforceability, RACT and

RACM requirements include the following:

Issues Relating to VOC Regulation, Cutpoints, Deficiencies, and Deviations (the "Blue Book"), US EPA, OAQPS (May 25, 1988).

2 PCAPCD also regulates a nonattainment area under the 2006 24

- Hour PM 2.5 National Ambient Air Quality Standard (NAAQS). 40 C.F.R. § 81.305 (2010) . By December 14, 2012, C alifornia must submit a revision to the State Implementation Plan (SIP) for this nonattainment area that provides for, among other things, implementation

of all RACM as expeditiously as practicable (including RACT for existing sources). CAA § 172 (a)(2)(A), (b) & (c)(1), 74 FR 58689 (Nov. 13, 2009). EPA will take action on this RACM demonstration in a separate rulemaking.Guidance Document for Correcting Common VOC and Other Ru le Deficiencies , EPA

Region IX (August 21, 2001, the “Little Bluebook”). State Implementation Plans; General Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990, 57 FR 13498 (April 16, 1992); 57 FR 18070 (April 28, 1992).

Sta te Implementation Plans; Nitrogen Oxides Supplement to the General Preamble; Clean Air Act Amendments of 1990 Implementation of Title I; Proposed Rule , 57 FR 55620 (Nov. 25, 1992)

. Final Rule To Implement the 8

- Hour Ozone NAAQS

– Phase 2 , 70 FR 71612 ( Nov. 25, 2005)

. Determination of Reasonably Available Control Technology and Best Available Retrofit Control Technology for Industrial, Institutional, and Commercial Boilers, Steam
Generators, and Process Heaters , CARB (July 18, 1991). http://www.arb.ca.gov/ractbarc/boilers.pdf Alternative Control Techniques Document

-- NOx Emissions from Industrial/Commercial/Institutional (ICI) Boilers

, US EPA 453/R

- 94

- 022 (March 1994). http://nepis.epa.gov/EPA/html/Pubs/pubtitleOAR.htm Alternative Control Techniques Document

-- NOx Emissions from Utility Boilers , US

EPA 452/R

- 93

- 008 (March 1994). http://nepis.epa.gov/EPA/html/Pubs/pubtitleOAR.htm State Implementation Plans (SIPs): Policy Regarding Excess Emissions During Malfunctions, Startup and Shutdown from Steven A. Herman, Assistant Administrator for Enforcement and Compliance Assurance, an d Robert Perciasepe, Assistant Administrator for Air and Radiation, September 20, 1999.

Evaluation of Rule Stringency As noted above, submitted Rule 233 must fulfill RACT requirements for NOx. See CAA § 182(b)(2) and (f); 40 CFR 51.912(a)

. EPA issues two types of guidance to assist states in determining what control techni ques meet the RACT requirement: control techniques guidelines (CTGs) and alternative control techniques (ACTs)

. CTGs establish the presumptive level of control meeting RACT, whereas ACTs describe available control techniques and their cost effectiveness, but do not define presumptive RACT levels. 70 FR 71654 (Nov. 25, 2005).

EPA has not issued a CTG for NOx for boilers

, but in 1994 EPA issued an ACT Document for

NOx emissions from Industr ial/Commercial/Institutional Boilers (1994 ACT )

.

As part of our evaluation of Rule 233, we reviewed t he 1994 ACT , which identifies NOx

emission levels for biomass

- fueled boilers ranging from 24 ppm to 187 ppm at 3% O 2 , based on

the use of SNCR controls w ith ammonia or urea injection. 1994 ACT at Appendix B , pages B20

- B21. This translates to a range of approximately 18 to 142 ppm at 12% CO 2

. This wide range of emission levels reflects the broad technical diversity among the types of boilers that fire bioma ss as fuel, including stokers, circulating fluidized bed boilers and bubbling fluidized bed boilers. It also reflects the variety of fuels that the term “biomass” covers, including various kinds of plant materials, wood materials and agricultural wastes.

In addition to reviewing the 1994 ACT, we obtained information about NOx emission limits in permits for biomass

- fueled boilers from the RACT/BACT/LAER Clearinghouse (RBLC

, http://cfpub.epa.gov/RBLC/ ) . We searched the RBLC for permits dated between 2001 an d 2011with process utility code 11.120 (Utility and Large Industrial Size Boilers/Furnaces (>250

MMBtu/hr), Biomass). The NOx emission limits in the se permits range between 0.01 lb/MMBtu (RBLC ID = GA

- 0132 , issued 2008 ) to 0. 6 lb/MMBtu (RBLC ID = NH

- 0013, issued 200 4 ), both for a 30 day rolling averaging period

. Th e s e limits translate to a range of approximately 5 to 328 ppm at 12% CO 2

. According to the RBLC, the 5 ppm limit has not been verified. The only permit found in the RBLC with a limit with a 3

- hou r averaging period similar to limit in Rule

233 is a limit of 0.3 lb/MMBtu, or approximately 164 ppm at 12% CO 2 (RBLC ID = AL

- 0250, issued 2010)

.

We also reviewed rules from other air districts in California that regulate biomass boilers. Yolo

Solano Air Quality Management Districted adopted a Biomass Boiler Rule (Rule 2.43) o n November 10, 2010 that limits NOx emissions to 90 ppm corrected to 3% O 2 on a 24

- hour block

average. This is approximately equal to 68 ppm at 12% CO 2

. San Joaquin Valley Unified Air Pollution Control District’s (SJVUAPCD) Solid Fuel Fired Boiler Rule (Rule 4352, adopted May 18, 2006) has a NOx emission limit for biomass boilers of 115 ppm at 3% O 2 on a 24

- hour block average, which translates to approximately 87 ppm at 12% CO 2

. We rec ently finalized a limited disapproval of SJVUAPCD rule because we determined that SJVUAPCD had not adequately demonstrated that the NO x limits in the rule satisfied RACT

.

Finally , we reviewed source test results for the only two currently existing facilit ies in Placer County that are subject to Rule 233. Source test results for both facilities for 2009 are shown i n the following table.

Facility Boiler Emission
Sierra Pacific Industries, Lincoln 289 MMBtu/hr, stoker 51.2 ppm at 12% CO 2 Rio Bravo Rockl in 356.8 MMBtu/hr, CFB 37.6 ppm at 12% CO 2 The source test results establish the emission levels that the facilities have been able to achieve in practice.

The NOx emission limit in submitted Rule 233 is 115 ppm at 12% CO 2 for a rolling 3

- hour averaging period. This limit

, which has been in place since the rule was first adopted in 1994, falls in the middle to high end of the range of achievable emission levels for biomass

- fired

boilers shown in the 1994 ACT (approximately 18 to 142 ppm at 12% CO 2 ) and n ear the middle of the range of limits in recent permits for this source category (approximately 5 to 328 ppm at
12% CO 2 ) . The limit is less stringent than those found in the analogous rules of oth er air districts in California. In addition, source test dat a show that the existing biomass

- fired boilers in Placer County that are subject to Rule 2 33 are achieving emission levels significantly below 115 ppm at

12 % C O 2

. EPA is not aware of any information indicating that these lower emission levels are

not reaso nably achievable in Placer County

Thus , although EPA previously approved Rule 233 as RACT for this source category under the

1

- hour ozone NAAQS, 61 FR 18959 ( April 30, 1996 ) , new information indica tes that the previous RACT determination is no longer appr opriate. See 70 FR 71652

. W e therefore propose

to determine that the PCAPCD has not adequately demonstrated that the NOx limit in Rule 233 (115 ppm at 12% CO 2 ) represents RACT.Evaluation of Enforceability and SIP Revision Criteria

Recordkeeping and othe r compliance provisions in the rule ensure that the requirements are adequately enforceable. The amendment of the Rule addresses EPA concern regarding the start

up and shutdown provisions and aligns these provisions with EPA guidance on the matter.

The su bmitted rule eliminates the less stringent NOx emission limit option and adds a more stringent emission limit for CO than the version previously approved into the SIP. As shown in the “Changes to the Rule” section above , t he new limits for start

- up and shu tdown periods are more stringent than the existing limits for each of the facilities currently subject to the rule

. Therefore, w e propose to determine that a limited approval of the sub mittal would comply with

CAA s ection 110(l) because (1) the proposed SI P revision would not interfere with the on

- going process for ensuring that requirements for RFP and attainment of the NAAQS are met, and (2) the submitted SIP revision is more stringent than the rule previously approved into the SIP. We

also propose to det ermine that a limited approval of the submittal would comply with CAA

s ection 193 because the submitted SIP revision is more stringent than the rule previously approved into the SIP and would insure equivalent or greater emission reductions of NOx and

CO.

Rule Deficiency As explained above under Evaluation of Rule Stringency, we believe that PC APCD has not

demonstrated that the NOx emission limits for biomass boilers implement RACT and that t he

NOx emission limits should be lowered to ensure implementatio n of RACT. Alternatively,

PC APCD may submit additional information to demonstrate that lower emission limits are not reasonably achievable.

Recommendation

EPA staff recommend s a limited approval and limited disapproval of PCAPCD Rule 233 under

CAA section s 110(k)(3) and 301(a).

Other References

1. RBLC permit information (AL

- 0250, GA

- 0132, NH

- 0013)

2. Source test results for Sierra Pacific Industries, Lincoln, 2009

3. Source test results for Rio Bravo Rocklin, 2009

4. Email from John Finne l l to Idalia Perez on 4/8/20 11

5. Submitted Rule 233

6. Staff Report for Rule 233

7. Current SIP

- approved version of Rule 233